The present invention relates to a device which prevents the entry of foreign or unwanted material into predetermined areas of a turbine assembly. The device can be utilized to temporarily seal substantially any desired opening on a turbine while the same is being assembled.
Energy supplying power plants, whether nuclear, hydro or fossil fueled, contain numerous turbine assemblies which play an integral part in energy production. Power shortages and outages have become increasingly more common and well publicized in recent years. Both experts and the press have highlighted the fact that few new power plants are being constructed to alleviate the dwindling power supply.
It is important that the turbines in power plants be constructed and maintained with the utmost efficiency. Loss of a large plant during a time of high power demand can cost over five million dollars per hour for replacement power or blackouts if replacement power is not available. The power plants alone can lose millions of dollars when a turbine is down for maintenance or due to breakage. Turbines have a large number of crevices and openings. During maintenance or assembly, small parts, screws, bolts, or other foreign objects can fall into these crevices. If not retrieved or noticed, these small parts have the potential to destroy a turbine and create hazardous situations such as by having a broken rotor piece explode through the turbine housing.
Various attempts of limited success have been made to combat the foreign material problem prior to the discovery of the present invention. One such attempt was the use of plywood to cover the sensitive areas of a turbine. The drawbacks of plywood were many, including difficulty in proper size formation and ability to secure the plywood in an opening. Further difficulties included the fact that once a turbine was assembled it was all but impossible to remove the plywood from inner portions of the turbine without breaking or partitioning the same, thus creating a further foreign material problem. Inflatable rubber air bladders have also been utilized to seal turbine openings with limited success. The bladders had to be continually monitored to make sure that proper air pressure was maintained to insure a good seal. The air bladders were heavy and had to be removed prior to turbine assembly, leaving the turbine completely exposed during this critical juncture.
It has been found by the inventors of the present invention that aforementioned problems can be avoided by utilizing a device which prevents small misplaced parts or foreign objects from gaining access to sensitive areas of a turbine assembly. It is also easily removable from an assembled turbine through existing man way openings; i.e. openings that are too small for existing devices.
The present invention relates to foreign material exclusion devices which can be used to prevent foreign materials from becoming lost or trapped within a turbine, more specifically predetermined areas of a turbine while being assembled or repaired. The foreign material exclusion devices preferably comprise an elastomer of resilient plastic or rubber or foam such as a plastic foam or rubber foam composition.
An important aspect of the present invention is that the foreign material exclusion devices can be placed in any desirable turbine opening or orifice at substantially any point during the assembly or repair process. Once the turbine is assembled the device can easily be removed.